Treatment of materials with binders in the briquetting of said materials



Patented Dec. 31, 1929 UNITED STATES RUDQLF LESS'ING, OF LONDON, ENGLAND TREATMENT OF MATERIALS WITH BINDERS IN THE BRIQUETTING OF SAID MATERIALS No Drawing; Application filed: October 6, 1927, Serial No. 224,513, and in Great. Britain. November 3, 1926.

In the briquetting of coal, coke, ores and other material, the binder most commonl employed is coal tar pitch. The use of pitc 1 is attended by a number of drawbacks; it. is

5 a: material difli-cult to grind to the requisite fineness, the ground pitch is liable to coalesce on: storage, the distribution of the ground pitch throughout the mass of material. to be briquetted is comparatively 1mto even, the particles of pitch are liable to run when melted and to swell when heated to the temperature of decomposition, thus weakenthe structure of the briquctte and finally the handling of pitch in powder form is ob jectionable on hygienic grounds, as it may cause pitch. cancer in persons coming in. con.- tact with it. Moreover, coal tar pitch is a material subject to violent price fluctuations.

I have found a method by which the advantages of pitch as abinder for materials for briquettes or aggregates may be retained and enchanced, whilst the disadvantages enumerated above will be obviated.

My invention is particularly appliable to the treatment of. material to: be briquetted such as anthracite, bituminous or other coal, coke, semi-coke, ores, metal scrap and. the like,.bu.t it. is also applicable to the treatment of material such as road metal for coating, 1

39 it with pitch.

One object of the present invention is to coat the individual particles with a layer of pitch so. asto enable them to be briquetted or otherwise bonded togetherby pressure at ordinary or but slightly elevated temperatures and for this purpose I coat the particles with a liquid product containing; a pitch like fraction. and an oily fraction Coal tar is the preferredproduct, but I may also. use other products obtained by the treatment of coal either by carbonization or by high pressure processes, or obtained from pctroleuin.

I then. remove from the treated particles the liquid. or oily fraction and leave the pitch like fraction asv a coating upon the individual particles.

Other objects will be apparent from the followingdescription and appended claims.

In the preferred form of invention, I innaphthene series. A small proportion of aromatic hydrocarbons may be present, but in this case the precipitation of the pitch or. bitumen is not so complete.

prior Patent No. 1,405,234; describes a process in: which the pitch is separated from coal tar by the use of a solvent within a cer tain range of. temperature, but according to the present invention, it is not necessary to adhere'to this temperature range and indeed it is remarkable that satisfactory results can be obtained by working in the cold, probablyv because the tar is disposed in thin films on the solid particles so that the oil can be extracted therefrom without the aid of. heat.

I may carry out this extraction intermittently or continuously and may remove the oil solution by any convenient method of draining, filtration or centrifuging, assisted by the application. of pressure or vacuum. I prefer to carry out the extraction methodically so that the filtrate obtained in the end is a very dilute oil solution or almost neat solvent.

The oil solution may be submitted to distillation with or without the application of live steam. for the purpose of the recovery of the solvent, which is then returned into the cycle.. and for the production of tar oils. lrVhere desired the tar acids and tar bases may be extracted. from. the oil solution. The oil recovered may be distilled, preferably while still hot, for the preparation of the ordinary tar fraction and the bituminous residue obtained may be added to the briquetting mixture.

The pitch coated material after extraction still contains a small amount of the solvent, which may be recovered by passing a current of steam through the mass, which should be superheated so as to avoid undue condensation. The mass is then ready for feeding into the briquetting machines which may be of the usual type.

W'here coal or coke is to be briquetted, I prefer to use it in a form as free as possible from ash, but my process will also deal with inferior fuels containing a high percentage of ash. If the material to be briquetted by my process is dried by application of heat, I may carry out the admixture of tar with the hot material coming from the dryer. The moist material can however be mixed with coal tar and I find that on extraction the water is removed with the solvent.

I have further found that the removal of the tar oil from the mixture may be assisted by the addition of certain reagents to the mixture. If, for instance, a small quantity of sulphuric acid is added to the tar coated material and thoroughly blended with it, the mixture becomes more granular and freerunning and less tacky than it was before the admixture of the acid, and in this condition, it is more readily extracted than'a mixture without the addition of acid.

The following may serve as an example.

100 parts of washed and dried anthracite duff are mixed with 20 parts of dehydrated coal tar, i. e. coal tar from which the water and the lower fractions of aromatic hydrocarbons have been removed and containing 50% of pitch. The tar is thoroughly n ixed with the duif mechanically to ensure coating of all the particles. 1 part of sulphuric acid which may be diluted with an equal volume of water is then added and thoroughly blended with the mixture. The mixture is charged into the extractor and petroleum spirit of B. P. 100-120 C. is allowed to percolate through it. The resulting solution of tar oil in spirit is drawn off and at the same time clean spirit is superimposed on the mixture and is allowed slowly to descend therethrough as a continuous unbroken body, so as to enable the solution to be withdrawn with the least possible dilution. The solution so with drawn has a steadily decreasing concentra tion of oil and the portion having a concentration of less than 10% of oil may be employed for the extraction of a fresh batch of mixture prior to the final extraction with neat solvent. The other portion containing up to 30% of oil is passed through a still for the recovery of the solvent and of the oil. After the mixture has been drained it may be freed from the remaining solvent by ste m. distillation in the same vessel, or it may be passed into a separate steaming Vessel while still hot. It is then fed into the briquetting presses.

Other tars may be employed but if the pitch content is higher, less may obviously be employed. Any fraction of petroleum can be employed as solvent which is substantially free from aromatic constituents e. g. a fraction boiling at 60 to 80 C. \Vith a higher acid solution of iron sulphate or chloride, and

the spent liquor from pickling steel is especially suitable.

. The burning qualities of coal briquettes may be modified by adding catalysts thereto and my invention allows of the addition of these compounds in the course of the mixing so that the catalyst can, if desired, be present mainly either on the surface of the coal particles or on the surface of the pitch film.

Briquettes made by my process on account of the more even distribution of thepitch 'ure more smokeless than those made with ground. pitch. 1 have found however that I can further improve the quality by subm1tting th m to a baking process at a tempera ture sufficiently high to keep the pitch in a fluxed condition and assist in its flowing, so as to cover the surface of the particles, but substantially below the initial decomposition temperature of the coal, though not nec-' essarily of the pitch.

The invention includes broadly a briquette formed of particles of coal material each individually coated with pitch and bonded together by pressure, especially a pressed briquette formed of particles of coal material such as anthracite in which the pitch has been fluxed around said particles by heat. The invention particularly included a hard dense briquctte of particles of anthracite bonded together by a coating of pitch upon and between the particles and carbonized in contact with the particles. It has been found that when the particles are individually coated with pitch they can be heated to a temperature sufficient to Carbonize the binder without appreciable decomposition of the anthracite. Such briquettes are hard and coke like but of high density and on account of the pitch having been carbonized burn without smoke. In general briquettes made by the present invention may be baked to atemperature suflicient to carbonize the binder in order to reduce the quantity of smoke on subsequent burning.

The invention is also applicable for the production of tar-macadam by treating road metal with tar, running off the excess liquid tlon.

I declare that what I claim is:

1. Process for the treatment of solid particles to be bonded together by pressure which consists in treating said particles with a liquid product containing an oily fraction and a pitch like fraction and then treating said particles with a solvent to remove said oily fraction but leave said pitch like fraction as a coating upon the individual particles.

2. Process for the treatment of solid particles to be briquetted which consists in treating said particles with a liquid product containing an oily fraction and a pitch like fraction and then treating the mixture with a liquid which is miscible with said oily fraction but a precipitant for said pitch like fraction so as to leave said particles coated with pitch like fraction.

3. Process for the treatment of solid particles to be briquetted which consists in treating said particles with a solution of pitch, then extracting said particles with a liquid miscible with the solvent but a precipitant for the pitch so as to leave said particles coated with pitch.

4. Process for the treatment of solid fuel particles to be briquettedwhich consists in treating said fuel particles with a liquid prodnot containing an oily fraction and a pitch like fraction and then treating the mixture with a liquid which is miscible with said oily fraction but a precipitant for said pitch like fraction so as to leave said fuel particles coated with the pitch like fraction.

5. Process for the treatment of solid fuel particles to be briquetted which consists in treating said fuel particles with a solution of pitch, then extracting said fuel particles with a liquid miscible with the solvent but a precipitant for the pitch so as to leave said fuel particles coated with pitch.

6. Process for the treatment of coal particles to be briquetted which consists in treating said coal particles with a liquid product containing an oily fraction and a pitch like fraction and then treating said coal particles with a solvent to remove said oily fraction but leave said pitch like fraction as a coating upon the individual coal particles.

5'- 7. Process for the treatment of solid particles to be bonded together by pressure which consists in treating said particles with a coal tar fraction containing an oily fraction and a pitch like fraction and then treating the mixture with a liquid which is miscible with said oily fraction but a precipitant for said pitch like fraction contained therein so as to leave said particles coated with the pitch like fraction.

8. Process for the treatment of solid fuel particles to be briquetted which consists in treating said fuel particles with a coal tar fraction containing an oily fraction and a pitch like fraction and then treating the mix-- ture with a liquid miscible with said oily fraction but a precipitant for said pitch like fraction so as to leave said fuel particles coated with the pitch like fraction.

9. Process for the treatment of coal particles to be briquetted which consists in treating said coal particles with a coal tar fraction containing an oily fraction and a pitch like fraction and then treating the mixture with a liquid miscible with said oily fraction but a precipitant for said pitch like fraction so as to leave said coal particles coated with the pitch like fraction.

10. Process for the treatment of solid particles to be bonded together by pressure which consists in treating said particles with a liquid product containing an oily fraction and a pitch like fraction and then treating the mixture with an organic solvent having a low content of aromatic constituents so as to extract said oily fraction of said liquid prodfraction and then treating the mixture with an organic solvent having a low content of aromatic constituents so as to extract said oily fraction of said liquid product and leave said coal particles coated with the pitch like fraction.

12. Process for the treatment of solid fuel particles to be briquetted which consists in treating said fuel particles with a coal tar fraction containing an oily fraction and a pitch like fraction and then treating the mixture with an organic solvent having a low content of aromatic constituents so as to extract said oily fraction and leave said fuel particles coated with the pitch like fraction.

13'. Process for the treatment of solid fuel particles to be briquetted which consists in treating said fuel particles with a solution of pitch then extracting said particles with a hydrocarbon liquid miscible with the solvent but a precipitant for the pitch so as to leave said fuel particles coated with pitch.

14. Process for the treatment of coal particles to be briquetted which consists in treating said coal particles with a liquid product containing an oily fraction and a: pitch like fraction and then treating said coal particles with a liquid petroleum product to remove said oily fraction but leave said pitch like fraction as a coating upon the individual coal particles.

15. Process for the treatment of solid particles to be briquetted which consists in treating said particles with a liquid product containing an oily fraction and a pitch like fraction and then treating the mixture with a hydrocarbon solvent having a low content of aromatic constituents so as to extract said oily traction of said liquid product and leave said particles coated with the pitch like fraction.

16. Process for the treatment of: solid particles to be bonded together by pressure which consists in treating said particles with a liquid product containn 3 an oily traction and pitch like fracti a and then treating the mixture with a continuous body of a liquid miscible with said oily traction but a precipitant for said pitch like traction so as to leave said particles coated with the pitch like fraction.

17. Process for the treatment of coal particles to be briquetted which consists in treating said coal particles with liquid product containing an oily traction and a pitch like fraction and then treating the mixture with a continuous body of a liquid miscible with said oily fraction but a precipitant for said pitch like traction so to leave said coal particles coated with the pitch like fraction.

18. Process for the treatment of solid fuel par cles to be briquetted which consists in trca i. said fuel particles with a liquid produc1 containing an oily fraction and a pitch l ke fraction and then treating the mix ture with a continuous body of solvent to move saidoily traction but leave said pitch like fraction a coating upon the individual particles.

19. Process for the treatment of solid par ticles to be briquetted which consists in treating said particles with a liquid product containin an oily traction and a pitch like "fraction and then treating the mixture with a continuous body of hydrocarbon. solvent having a low content oi aromatic constituents so as to extract said oily fraction of said liquid product and leave said particles coated with the pitch like fraction.

20. Process for the treatment of coal particles to be briquetted which consists in treating said coal particles with a liquid product containing an oily fraction and a pitch like fraction, mixing therewith an acid liquid and then treating the mixture with an organic solvent having a low content of aromatic constituents so as to extract said oily traction of said liquid product and leave said coal particles coated with the pitch like fraction.

21. Process for the manufacture of briquettes from coal particles which consists in treating said coal particles with a liquid product containing an oily fraction, treating the mixture with an organic solvent having a low content of aromatic constituents so as to extract said oily traction of said liquid product and leave said coal particles coated with the pitch like fraction, bonding the particles bv pressure and baking the briquettes said coal particles coated with said pitch like traction, bonding the particles by pressure and bakin the briquettes so formed at a temperature sutlicient to flux and carbonize said pitch traction around said coal particles.

23. Process for the treatment of anthracite particles to be briquetted which consists in treating said anthracite particles with a liquid product containing an oily fraction and a pitch like fraction and then treating the mixture with an organic solvent having a low content of aromatic constituents so as to extract said oily fraction of said liquid product and leave said anthracite particles coated with the pitch like fraction.

Process for the treatment of coal particles to be briquetted which consists in treatin g said coal particles with a coaltar fraction containing an oily traction and a pitch like fraction, mixing therewith an acid liquid, 1hen treating the mixture with hydrocarbon solvent having a low content of aromatic constituents so as to remove said oily fraction but leave said pitch like fraction as a coatingupon the individual particles.

In witness whereof, I have hereunto signed my name this 21st day of September, 1927.

RUDOLF LESSING. 

